In numerous applications, where driving for rotation is necessary, the so-called "universal" motor is presently used. This motor is simple, is small in size for a predetermined output, and can rotate at relatively high speeds, usually higher than 5000 rpm, which is particularly valuable for means for driving gaseous fluids such as fans, blowers, and in particular hair dryers. Nevertheless, this type of universal motor, which includes a mechanical collector and brushes, has major disadvantages associated with the wear of these elements, spark erosion due to poor commutation, the generation of interference, and the noise it produces.
Electronic commutation motors make it possible to dispense with the collector and brushes of universal motors, but generally involve relatively expensive components that substantially increase the price of the motor.
Moreover, until now, it had been commonly acknowledged that the electronic commutation motor, with reluctance pads, was incapable of functioning correctly except at relatively low rotational speed, for example on the order of 2000 rpm. It was believed that at higher speeds, especially above 5000 rpm, it was no longer possible for such a motor with electronic commutation to function correctly, because of the major antagonistic effect of the reluctance torque at these speeds.